1. Field of the Invention
The present invention relates to hydraulic couplings used in undersea drilling and production applications and seals used in those couplings. More particularly, the invention involves an undersea hydraulic coupling with radial seals on the probe of the male coupling member.
2. Description of Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with soft seals positioned within the female member to seal the junction between the male and female members. The female member is generally a cylindrical body with a relatively large diameter longitudinal bore at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore contains soft seals and receives the male portion of the coupling. The male member includes a cylindrical portion, or probe, at one end having a diameter approximately equal to the diameter of the large bore of the female portion of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to the various embodiments of the device, the soft seals, or O-rings, either abut the end or face of the male member or engage the cylindrical probe wall about its outer circumference. The hydraulic fluid is then free to flow through the female and male members of the coupling, and seals prevent that flow from escaping about the joint and the coupling. Typically, the male and female members of undersea hydraulic couplings are attached to opposing manifold plates.
In some instances, a check or poppet valve may be installed in the female member and also in the male member. Each valve opens when the coupling is made up and closes when the coupling is broken so as to prevent fluid from leaking out of the system of which the coupling is a part.
The seals used in undersea hydraulic couplings should, if possible, be reusable. After the coupling members are separated, the coupling can be made up again and effectively seal hydraulic fluid in the internal passages of the coupling members, and effectively seal out sea water. The effectiveness of the seals is critical, particularly when the couplings are subject to high pressures at depths of several thousand feet or more.
U.S. Pat. Nos. 4,694,859 and 5,762,106 to Robert E. Smith, III, assigned to National Coupling Co., Inc. of Stafford, Tex., disclose undersea hydraulic couplings having pressure energized metal seals retained in the female coupling member for sealing between the male and female coupling members. A seal retainer holds the seal in the female coupling member. When the male and female members of the coupling are parted under pressure, the retainer does not blow out through the bore of the female member.
U.S. Pat. Nos. 4,900,071 and 5,052,439 to Robert E. Smith, III, assigned to National Coupling Co., Inc., disclose undersea hydraulic couplings with annular elastomeric seals retained in the female coupling member by a two-piece retainer. The seal is restrained from radial movement by an interfit with the retainer. When the coupling is parted under pressure, the seal does not blow out through the bore of the female member.
U.S. Pat. No. 5,232,021 to Robert E. Smith, III, assigned to National Coupling Co., Inc., discloses a probe for an undersea hydraulic coupling having at least one circumferential depression in its outer cylindrical body, for disengaging one or more radial seals during insertion or withdrawal of the probe from the receiving member of a coupling. Disengagement of the radial seals allows seawater to bleed from or into the space between the coupling members and thereby balance the coupling and seals to seawater pressure.
U.S. Pat. No. 5,983,934 to Robert E. Smith, III, assigned to National Coupling Co., Inc., discloses an undersea hydraulic coupling with a male member having a stepped outer body that may be inserted into a female member which has retained therein three seals and a three part seal retaining member. Two of the seals engage different diameters of the male member, prior to opening of the valves in the male and female members.
The metal and/or elastomeric seals positioned in the female member of undersea hydraulic couplings are designed to be reusable. After repeated engagement and disengagement of the coupling members, the seals may become worn or damaged. A leak path may form around or through a worn or damaged seal, allowing hydraulic fluid to leak out from the coupling and/or seawater to enter into the coupling. Replacement of seals can cause significant delay and expense. To replace the seals, the manifold plate with the female coupling members must be retrieved and brought to the surface, the seals replaced, and the manifold plate repositioned and the couplings reconnected subsea.
It is desirable to extend the life of the female coupling members before the seals are replaced. It also is desirable to keep the female coupling members subsea when they are disconnected from the male coupling members. This reduces the time and cost for retrieval. If the female coupling members stay subsea when they are disconnected, their seals and sealing surfaces are exposed to and may become damaged by silt and marine growth.
An improved undersea hydraulic coupling is needed that will eliminate or minimize the need to retrieve female coupling members and replace seals held therein. An improved undersea hydraulic coupling also is needed having a male member that fits and sealingly engages female coupling members that have worn seals. An improved undersea hydraulic coupling also is needed that will extend the life of female coupling members having worn or damaged seals.
The present invention resides in an undersea hydraulic coupling of the foregoing type including male and female members for fluid communication therebetween and valves for controlling fluid flow in each of the members. The present invention includes a male member having radial seals around the probe. The seals on the probe block a potential leak path, and provide the primary sealing mechanism between the male and female coupling members when the seals retained in the female coupling member are worn or damaged.